Air boom spreader for particulate material

ABSTRACT

An air-boom spreader has a hopper for containing particulate material, a metering device having a plurality of sluices, a plurality of outlets transversely spaced-apart on a boom in a direction perpendicular to the direction of travel of the spreader, and a plurality of air lines connecting the plurality of sluices to the plurality of outlets for conveying the particulate material in an air stream from the plurality of sluices to the plurality of outlets. The spreader has more than twice as many outlets as sluices, and the plurality of outlets has an innermost outlet, an outermost outlet and at least three other outlets between the innermost outlet and the outermost outlet whereby each of the innermost outlet and the outermost outlet are supplied with half as much of the particulate material as each of the at least three other outlets.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication U.S. Ser. No. 62/908,132 filed Sep. 30, 2019, the entirecontents of which is herein incorporated by reference.

FIELD

This application relates to agriculture, in particular to a method andan apparatus for applying solid agricultural product to a field.

BACKGROUND

In modern agriculture, many crops (e.g. corn) are often planted byseeding a field with seed in evenly-spaced parallel rows. Seeding afield generally involves towing a seeding implement behind a towingvehicle (e.g. a tractor) such that the wheels of the towing vehicle andthe wheels of the seeding implement follow the same path, and the seedsare planted in crop rows spaced-apart by a distance such that the wheelsare between crop rows. The seeding implement generally has a pluralityof transversely spaced-apart seed outlets so that a plurality of croprows may be planted at the same time in a single swath as the towingvehicle drives in a driving line in one direction on the field.Currently, all such seeding implements comprise an even number of seedoutlets, for example 12, 16, 18, 24, 36, 48, etc. seed outlets. When thetowing vehicle and the seeding implement arrive at the end of the field,the towing vehicle and the seeding implement are shifted over and drivenin a new driving line in the opposite direction to plant another swathof crop rows. The new driving line is chosen so that the spacing betweenall of the parallel crop rows in the field remains constant across thefield. The new driving line is determined based on the location in thefield of the previous driving line and on the number and spacing of seedoutlets on the seeding implement. The driving lines may be stored ascoordinates in a global positioning system (GPS) for future referenceand/or for automating the planting.

After planting, it is often desirable to apply post-planting product(e.g. fertilizer, micronutrients, etc. or mixtures thereof) in betweenthe crop rows (i.e. mid-rows). A different implement but the same towingvehicle are often used for application of post-planting product. Becauseaxle width of the towing vehicle remains unchanged, to avoid driving onthe crop rows during post-planting product application, the towingvehicle is driven on the same driving lines as was driven duringplanting. In order to apply post-planting product between the crop rowsunder such conditions, the implement used to apply post-planting producthas a plurality of product outlets spaced-apart by substantially thesame or a similar distance as the seed outlets on the seeding implement,but the outlets on the post-planting implement are transversely offsetwith respect to a centerline of the towing vehicle by an amount equal toabout half the spacing distance. Alternative to towing a post-plantingimplement, a self-propelled vehicle may be used to apply post-plantingproduct to the field. Nevertheless, the self-propelled vehicle shoulddrive between rows and it is desirable for the self-propelled vehicle todrive on the same rows as the towing vehicle that towed the seedingimplement in order to prevent excessive compaction. Such a practice iscalled tramlining where all traffic drives in same rows as much aspossible.

Unfortunately, such a practice results in some mid-rows receiving twicethe desired amount of post-planting product, or some mid-rows receivingno post-planting product, or some mid-rows receiving twice the desiredamount of post-planting product and others receiving none. The problemcould be mitigated by shifting every second driving line duringapplication of the post-planting product. However, shifting every seconddriving line is generally undesirable due to the difficulty in feedingfrom a fixed set of endless belts or meter rollers into a sluicedmetering device and having a moveable boom to switch between rows. Sucha solution requires many more moving parts, which can jam, wear out frommovement and experience other problems associated with moving parts.

Recently, an apparatus and method have been developed in which theoutlets of a particulate material spreader are configured to receive theparticulate material from a metering device and to dispense an amount ofthe particulate material to mid-rows between crop rows on a field suchthat the plurality of outlets dispenses half the amount of particulatematerial to an outermost mid-row compared to the amount of particulatematerial dispensed to the other mid-rows (see International PatentPublication WO 2018/170594 published Sep. 27, 2018, the entire contentsof which is herein incorporated by reference). Such a configurationpermits delivering the same amount of particulate material to eachmid-row as the towing vehicle tramlines through a field. However, inair-boom spreaders with a configuration of air lines as shown in WO2018/170594, as the total span of the boom exceeds 60 feet (about 18.5meters), insufficient distribution of particulate material to certainoutlets, e.g. the outermost outlets, may occur at the typical particledistribution rates and vehicle speeds used, i.e. 400 lb/acre at 14 mphor 560 lb/acre at 10 mph. A goal of using longer booms (e.g. 90-foottotal boom span) is to distribute particulate material at a higher rate,e.g. 1200 lb/acre at a vehicle speed of 10 mph, in order to performbroadcasting and row cropping. However, increasing the particledistribution rate in such a way may also lead to line plugging,particularly at the innermost outlets, when a boom having a total spanin excess of 60 feet is used.

There still remains a need for a post-planting implement, particularlyan air-boom spreader with a total boom span of greater than 60 feet, anda method for applying the same amount of a particulate material to allthe mid-rows between crop rows while the spreader is driven on the samedriving lines used for planting the crop rows.

SUMMARY

There is provided an air-boom spreader for spreading particulatematerial on a field, the spreader comprising: a hopper for containingthe particulate material; a metering device comprising a plurality ofsluices, the metering device receiving the particulate material from thehopper and partitioning the particulate material into the plurality ofsluices; a plurality of outlets transversely spaced-apart on a boom in adirection perpendicular to the direction of travel of the spreader; and,a plurality of air lines connecting the plurality of sluices to theplurality of outlets for conveying the particulate material in an airstream from the plurality of sluices to the plurality of outlets,wherein there are more than twice as many outlets as there are sluices,and wherein the plurality of outlets comprises an innermost outlet, anoutermost outlet and at least three other outlets between the innermostoutlet and the outermost outlet whereby each of the innermost outlet andthe outermost outlet are supplied with half as much of the particulatematerial as each of the at least three other outlets.

There is also provided an air-boom spreader for spreading particulatematerial to mid-rows between crop rows on a field, the spreadercomprising: a hopper for containing the particulate material; a meteringdevice configured to receive the particulate material from the hopper; aplurality of outlets transversely spaced-apart on a boom in a directionperpendicular to a direction of travel of the spreader and configured toreceive the particulate material from the metering device and todispense the particulate material to the mid-rows, the plurality ofoutlets comprising a pair of distal-most outlets in relation to themetering device, the pair of distal-most outlets comprising an outermostoutlet and a penultimate outlet, an innermost outlet in relation to themetering device, and a pair of interior outlets situated on the boombetween the pair of distal-most outlets and the innermost outlet; and, aplurality of air lines connecting the metering device to the pluralityof outlets for conveying the particulate material in an air stream tothe plurality of outlets, the plurality of air lines comprising a firstair line connecting the metering device to the pair of distal-mostoutlets, the metering device supplying 1.5 units of the particulatematerial to the first air line, the first air line configured to conveyone-third of the 1.5 units of the particulate material to the outermostoutlet and two-thirds of the 1.5 units of the particulate material tothe penultimate outlet, a second air line connecting the metering deviceto the innermost outlet and the pair of interior outlets, the meteringdevice supplying 2.5 units of the particulate material to the second airline, the second air line configured to convey one-fifth of the 2.5units of the particulate material to the innermost outlet and two-fifthsof the 2.5 units of the particulate material to each outlet of the pairof interior outlets.

There is also provided an air-boom spreader for spreading particulatematerial on a field, the spreader comprising: a hopper for containingthe particulate material; a metering device for partitioning theparticulate material, the metering device comprising first and secondmetering elements, each metering element receiving the particulatematerial from the hopper, and first and second sluice boxes, the firstsluice box having a first plurality of sluices therein that receive theparticulate material from the first metering element, the second sluicebox having a second plurality of sluices therein that receive theparticulate material from the second metering element; and, a boomtransversely extendible in opposite transverse directions distally fromthe metering device substantially non-parallel to a direction of travelof the spreader and substantially non-perpendicular to the field, theboom comprising a plurality of outlets transversely spaced-apart in adirection perpendicular to the direction of travel of the spreader, theplurality of outlets comprising a first pair of distal-most outletssituated on a first side of the spreader, the first pair of distal-mostoutlets comprising a first outermost outlet and a first penultimateoutlet, a second pair of distal-most outlets situated on a second sideof the spreader, the second pair of distal-most outlets comprising asecond outermost outlet and a second penultimate outlet, a center outletsituated over a central travel line of the spreader, a first pair ofinterior outlets situated between the first pair of distal-most outletsand the center outlet, a second pair of interior outlets situatedbetween the second pair of outermost outlets and the center outlet, anda plurality of air lines connecting the first and second plurality ofsluices to the plurality of outlets for conveying the particulatematerial in an air stream to the plurality of outlets, the plurality ofair lines comprising a first outermost-extending air line connecting afirst outermost-supplying sluice situated among the first plurality ofsluices to the first pair of distal-most outlets, the firstoutermost-supplying sluice supplying a first 1.5 units of theparticulate material to the first outermost-extending air line, thefirst outermost-extending air line configured to convey one-third of thefirst 1.5 units of the particulate material to the first outermostoutlet and two-thirds of the first 1.5 units of the particulate materialto the first penultimate outlet, a second outermost-extending air lineconnecting a second outermost-supplying sluice situated among the secondplurality of sluices to the second pair of distal-most outlets, thesecond outermost-supplying sluice supplying a second 1.5 units of theparticulate material to the second outermost-extending air line, thesecond outermost-extending air line configured to convey one-third ofthe second 1.5 units of the particulate material to the second outermostoutlet and two-thirds of the second 1.5 units of the particulatematerial to the second penultimate outlet, a first centrally-extendingair line connecting a first centrally-supplying sluice situated amongthe first plurality of sluices to the center outlet and the first pairof interior outlets, the first centrally-supplying sluice supplying afirst 2.5 units of the particulate material to the firstcentrally-extending air line, the first centrally-extending air lineconfigured to convey one-fifth of the first 2.5 units of the particulatematerial to the center outlet and two-fifths of the first 2.5 units ofthe particulate material to each outlet of the first pair of interioroutlets, and a second centrally-extending air line connecting a secondcentrally-supplying sluice situated among the second plurality ofsluices to the center outlet and the second pair of interior outlets,the second centrally-supplying sluice supplying a second 2.5 units ofthe particulate material to the second centrally-extending air line, thesecond centrally-extending air line configured to convey one-fifth ofthe second 2.5 units of the particulate material to the center outletand two-fifths of the second 2.5 units of the particulate material toeach outlet of the second pair of interior outlets.

Further features will be described or will become apparent in the courseof the following detailed description. It should be understood that eachfeature described herein may be utilized in any combination with any oneor more of the other described features, and that each feature does notnecessarily rely on the presence of another feature except where evidentto one of skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

For clearer understanding, preferred embodiments will now be describedin detail by way of example, with reference to the accompanyingdrawings, in which:

FIG. 1 depicts a rear perspective view of one embodiment of an air-boomspreader of the present invention;

FIG. 2 depicts the spreader of FIG. 1 without drop tubes;

FIG. 3A depicts a magnified rear perspective view of a central portionof the spreader of FIG. 2;

FIG. 3B depicts a magnified rear perspective view of a central portionof the spreader of FIG. 2 without sluice boxes;

FIG. 3C depicts a magnified side view of a cut-away of a rear portion ofthe spreader of FIG. 2;

FIG. 4 depicts a top front perspective view of sluice boxes and airmanifold of the spreader of FIG. 2;

FIG. 5 depicts a bottom front perspective view of FIG. 4;

FIG. 6 depicts a top rear perspective view of sluice boxes and airmanifold of the spreader of FIG. 2 without upper funnel portions on thesluice boxes;

FIG. 7 depicts a top front perspective view of FIG. 6;

FIG. 8 depicts a rear view of FIG. 6;

FIG. 9 depicts a bottom view of FIG. 6;

FIG. 10 depicts a top view of FIG. 6;

FIG. 11 depicts a front view of FIG. 6;

FIG. 12 depicts a sectional view through A-A in FIG. 11 at a scale of1:12;

FIG. 13 depicts a magnified view of a central portion of FIG. 12;

FIG. 14 depicts a magnified view of a just-off-center portion of FIG.12;

FIG. 15 depicts a rear sectional view taken vertically through thesluice boxes and air manifold depicted in FIG. 4;

FIG. 16 depicts a bottom view of a left side of a boom of the spreaderof FIG. 2 at a scale of 1:56;

FIG. 17 depicts a magnified bottom sectional view of a left side distalend of the boom depicted in FIG. 16;

FIG. 18 depicts a bottom view of a central portion of an air-boomspreader having an alternate embodiment of an air manifold; and,

FIG. 19 depicts a magnified view of a cross-section of a just-off-centerportion of the air-boom spreader of FIG. 18.

DETAILED DESCRIPTION

The present invention provides an air-boom spreader and a method forapplying the same amount of a particulate material to all mid-rowsbetween crop rows in a field while the spreader is tramlining in thefield; that is, while the spreader is being driven in the field on thesame driving lines used for planting the crop rows. The air-boomspreader works well for all boom spans, even booms with a total boomspan of greater than 60 feet, for example a boom span between 80 feetand 100 feet (e.g. 90 feet). The particulate material may be a solidagricultural product, for example fertilizer, a micronutrient, agranular herbicide, a cover crop seed for interrow seeding or anymixture thereof. The particulate material is preferably a post-plantingproduct.

The spreader may be self-propelled, mounted on a prime mover (e.g. atruck or tractor) or towed behind a prime mover. The spreader comprisesa hopper for containing the particulate material, a metering device forreceiving the particulate material from the hopper, a boom, a pluralityof outlets transversely spaced-apart on the boom in a directionperpendicular to the direction of travel of the spreader and a pluralityof air lines connecting the metering device to the plurality of outletsso that the particulate material can be conveyed from the meteringdevice to the plurality outlets to be dispensed to the mid-rows betweenthe crop rows in the field. The spreader may further comprise a blowerin fluid communication with the plurality of air lines for providing anair stream in the plurality of air lines to convey the particulatematerial through the air lines.

The boom is extendible transversely from metering device substantiallynon-parallel to a direction of travel of the spreader and substantiallynon-perpendicular to the field. The boom may comprise one or more thanone boom section. The boom may be transversely extendible to one or bothsides of spreader in opposite transverse directions from the spreader.

The metering device preferably comprises a metering element and aplurality of sluices, the metering element receiving the particulatematerial from the hopper and the plurality of sluices receiving theparticulate material from the metering element. The plurality of sluicesis preferably housed in a sluice box. The metering device may compriseone or more metering elements. The metering device may comprise one ormore plurality of sluices. In some embodiments, the metering device maycomprise two or more metering elements. In some embodiments, themetering device may comprise two or more plurality of sluices. Where themetering device comprises more than one metering element, the meteringelements may be controlled together to supply the particulate materialto sluice boxes at the same rate, or may be independently controllableto independently supply the particulate material to sluice boxes at thesame rate or at different rates as desired, each sluice box housing itsown plurality of sluices. For example, one or more metering elements maybe turned completely off while one or more other metering elements maybe on.

The metering element may comprise an endless belt or a set of meterrollers. Where there is more than one metering element, the meteringelements may be the same type or different types of metering elements.Endless belts may be independently controllable using dedicated motors,while sets of meter rollers may be independently controllable usingdedicated clutches to engage and disengage the sets of meter rollers.

The plurality of outlets comprises a minimum of five outlets includingan innermost outlet, an outermost outlet and at least three otheroutlets between the innermost outlet and the outermost outlet. Theinnermost outlet and the outermost outlet are supplied with half as muchof the particulate material as the at least three other outlets so thatwhile tramlining in the field, the spreader can dispense the same amountof the particulate material to all of the mid-rows. The innermost outletis preferably over a mid-row on a central travel line of the spreader,while the outermost outlet is over an outermost mid-row while thespreader is being driven in the field.

It is of special note that there are more than twice as many outlets asthere are sluices. Thus, each sluice supplies the particulate materialto at least two of the plurality of outlets. It has been found thatsupplying the outermost outlet and a penultimate outlet with particulatematerial from the same sluice, and by supplying the innermost outlet anda pair of interior outlets from the same sluice, the spreader isconfigured to evenly distribute the particulate material to the outletsat both the distal and proximal ends of the boom without plugging theair lines at the proximal end. The three other outlets thus comprise thepair of interior outlets and the penultimate outlet, and the pair ofinterior outlets are between the penultimate outlet and the innermostoutlet. Such an arrangement permits using a longer boom (e.g. greaterthan 60 feet total span) without unduly affecting the evenness ofparticulate material distribution along the entire span of the boom sothat each mid-row always receives the same amount of particulatematerial.

In order for the sluices to supply more than one outlet, the air linesleading from the sluices to the outlets are provided with flow dividers.Flow dividers for particulate materials in air lines are generally knownin the art. In the present spreader, a first flow divider in a first airline that conveys 1.5 units of the particulate from anoutermost-supplying sluice to the outermost and penultimate outlets isused to divide the 1.5 units of the particulate into a one-third portionand a two-thirds portion, the one-third portion being conveyed to theoutermost outlet and the two-thirds portion being conveyed to thepenultimate outlet so that the outermost outlet dispenses 0.5 units ofthe particulate material while the penultimate outlet dispenses 1 unitof the particulate material. Further, second and third flow dividers ina second air line that conveys 2.5 units of the particulate from anothersluice to the innermost outlet and the pair of interior outlets are usedto properly divide the particulate material. The second flow dividerdivides the 2.5 units of the particulate material into a one-fifthportion conveyed to the innermost outlet and a four-fifths portionconveyed to the pair of interior outlets. The third flow divider dividesthe four-fifths portion into two two-fifths portions to each of theoutlets of the pair of interior outlets. In this manner, the innermostoutlet dispenses 0.5 units of the particulate material while each of theoutlets of the pair of interior outlets dispenses 1 unit of theparticulate material.

Where the boom is extendible to both sides of the spreader in theopposite transverse directions from the spreader, the innermost outletmay be termed a center outlet. In such an arrangement, a firstcentrally-extending air line supplied by a first centrally-supplyingsluice of the first sluice box and a second centrally-extending air-linesupplied by a second centrally-supplying sluice of the second sluice boxboth convey particulate material to the center outlet so that the centeroutlet dispenses 1 unit of the particulate material to the mid-row onthe central travel line of the spreader.

In addition to at least three other outlets (i.e. the penultimate outletand the pair of interior outlets), the plurality of outlets preferablyfurther comprises at least one further pair of other outlets situated onthe boom. The at least one further pair of other outlets may be situatedbetween the pair of interior outlets and the penultimate outlet orbetween the pair of interior outlets and the innermost outlet. However,for efficient use of the air lines, the at least one further pair ofother outlets is preferably situated between the pair of interioroutlets and the penultimate outlet.

The total number of sluices and outlets depends on the desired boomspan. Preferably, the spreader comprises a total of at least 7 sluicesand 15 outlets. In one embodiment, the spreader comprises a total of atleast 8 sluices and 17 outlets. In other embodiments, especially wherethe boom is extendible to both transverse sides of the spreader, thespreader comprises a total of at least 16 sluices and 33 outlets, or atotal of 18 sluices and the plurality of outlets comprises a total of 37outlets.

The use of the term “unit” throughout the specification refers to asingle quantity regarded as a whole for the amount of particulatematerial that is desired to be dispensed through one outlet in order todeliver the particulate material at a desired rate (i.e. weight perarea) to each mid-row in the field in a single pass. Further, eachindividual outlet could be arranged as a plurality of sub-outlets,provided the sub-outlets of an individual outlet dispense theparticulate material to the same mid-row in the field.

With reference to FIG. 1 to FIG. 17, one embodiment of an air-boomspreader 100 is illustrated. The spreader 100 comprises a prime mover,for example a truck 102, a hopper 40 supported on a chassis 103 of thetruck 102, a metering device 50 mounted on the bed of the truck 102 at arear of the truck 102 and an air-boom 80 mounted on the bed of the truck102 at the rear of the truck 102. The air-boom 80 has a total span ofabout 90 feet and comprises a first boom section 80 a, a second boomsection 80 b, and a central boom section 80 c, the first boom section 80a extendible transversely left from the metering device 50 and thesecond boom section 80 b extendible transversely right from the meteringdevice 50. The boom sections 80 a, 80 b have proximal and distal ends,whereby the proximal ends are closer to the metering device than thedistal ends. In this embodiment, the air-boom 80 is substantiallyperpendicular to a direction of travel of the truck 102 andsubstantially parallel to a field during operation of the spreader 100.The boom sections 80 a, 80 b are foldable through a substantiallyhorizontal plane so that the boom sections 80 a, 80 b are substantiallyparallel to the direction of travel of the truck 102 duringtransportation along a roadway. The truck 102 has wheels 104 (only onelabeled) for driving in fields and on roadways.

In the illustrated embodiment, the metering device 50 comprises sluiceboxes, which comprise a first sluice box 53 and a second sluice box 54.The metering device 50 further comprises metering elements. The meteringelements comprise a first set of meter rollers 51 and a second set ofmeter rollers 52 above the sluice boxes 53, 54, respectively, and fourendless belts 56 a, 56 b, 56 c, 56 d behind the sluice boxes 53, 54. Theendless belts 56 a, 56 b, 56 c, 56 d comprise a first upper endless belt56 a, a first lower endless belt 56 b, a second upper endless belt 56 cand a second lower endless belt 56 d. The first and second sets of meterrollers 51, 52 are situated to deliver particulate material to thesluice boxes 53, 54, respectively. The first upper and first lowerendless belts 56 a, 56 b are situated to deliver particulate material tothe first sluice box 53. The second upper and second lower endless belts56 c, 56 d are situated to deliver particulate material to the secondsluice box 54.

The sets of meter rollers 51, 52 and the four endless belts 56 a, 56 b,56 c, 56 d receive particulate material from the hopper 40, the endlessbelts 56 a, 56 b, 56 c, 56 d extending into the hopper 40. Particulateagricultural material contained in the hopper 40 is supplied to the setsof meter rollers 51, 52 and the endless belts 56 a, 56 b, 56 c, 56 d bygravity. The sets of meter rollers 51, 52 are driven by a common motor,but are independently controllable by dedicated clutches, which engageand disengage their respective sets of meter rollers 51, 52 to turn thesets of meter rollers 51, 52 on and off. The endless belts 56 a, 56 b,56 c, 56 d are each independently controlled by dedicated motors 57 a,57 b, 57 c, 57 d, respectively. Therefore, one side or the other of themetering device 50 may be shut off to permit distribution of particulatematerial to only one side of the spreader 100, if desired.

On a given side of the metering device 50, one or more of the meteringelements may be used to deliver the particulate material to the sluiceboxes. For example, the first and second sluice boxes 53, 54 may receivethe particulate material from the first and second sets of meter rollers51, 52, respectively, but not from the endless belts 56 a, 56 b, 56 c,56 d. Any one or more of the set of meter rollers and endless belts on agiven side of the metering device may be used to deliver the particulatematerial to the sluice box on that side. The first sluice box 53comprises a first upper funnel portion 53 a and a first lower funnelportion 53 b. The second sluice box 54 comprises a second upper funnelportion 54 a and a second lower funnel portion 54 b. Dividing fins inthe funnel portions 53 a, 53 b of the first sluice box 53 define 9sluices 55 a, 55 b, 55 c, 55 d, 55 e, 55 f, 55 g, 55 h, 55 i. Dividingfins in the funnel portions 54 a, 54 b of the second sluice box 54define another 9 sluices 55 j, 55 k, 55 l, 55 m, 55 m, 55 o, 55 p, 55 q,55 r. The metering device 50 therefore comprises a total of 18 sluices55 a-55 r. The sluices 55 i, 55 j are wide, being configured to supply1.25 times as much particulate material than the sluices 55 b-55 h and55 k-55 q. The sluices 55 a, 55 r are narrow being configured to supply0.75 times as much particulate material as the sluices 55 b-55 h and 55k-55 q.

The air-boom 80 further comprises an air manifold having a centralairbox 81 for supporting various components of the air manifold and forproviding air to other parts of the air manifold. The air manifoldcomprises 18 air lines 82 a, 82 b, 82 c, 82 d, 82 e, 82 f, 82 g, 82 h,82 i, 82 j, 82 k, 82 l, 82 m, 82 n, 82 o, 82 p, 82 q, 82 r supported onand in fluid communication with the airbox 81. The air lines 82 a-82 rare supplied with particulate material from the 18 sluices 55 a-55 r,respectively. Defining 1 unit of particulate material as describedabove: the sluices 55 a and 55 r supply 1.5 units of the particulatematerial to the air lines 82 a and 82 r, respectively; the sluices 55 iand 55 j supply 2.5 units of the particulate material to the air lines82 i and 82 j, respectively; and, the sluices 55 b, 55 c, 55 d, 55 e, 55f, 55 g, 55 h, 55 k, 55 l, 55 m, 55 m, 55 o, 55 p, 55 q supply 2 unitsof the particulate material to the air lines 82 b, 82 c, 82 d, 82 e, 82f, 82 g, 82 h, 82 k, 82 l, 82 m, 82 n, 82 o, 82 p, 82 q, respectively.

The air lines 82 a-82 r of the air-boom 80 are equipped with a total of37 outlets 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,36, 37. The outlets 1-37 may be equipped with drop tubes 38 (only onelabeled) and/or with deflectors 39 (see FIG. 3A, only one labeled) tohelp guide the particulate material from the outlets 1-37 to the fieldbelow. The 18 air lines 82 a-82 r convey the particulate material to the37 outlets 1-37 in an air stream. The air stream is generated by ablower 82 that blows air through a main duct 83 into the airbox 81 andthen into the air lines 82 a-82 r. The air manifold further comprises abooster hose 84 in fluid communication with airbox 81 and the outlet 19to provide extra air flow through the outlet 19 to help prevent pluggingof the outlet 19 during operation. The booster hose may be omitted ifthere is sufficient air flow without the booster hose.

The outlets 1 and 2 are a pair of distal-most outlets on the left sideof the spreader 100. The outlets 36 and 37 are another pair ofdistal-most outlets on the right side of the spreader 100. The outlet 19is a center outlet located over a central travel line T-T (see

FIG. 16) of the spreader 100. The outlets 17 and 18 are a pair ofinterior outlets on the left side of the spreader 100. The outlets 20and 21 are another pair of interior outlets on the right side of thespreader 100. The other outlets 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 arepaired, with outlet pairs 3/4, 5/6, 7/8, 9/10, 11/12, 13/14, 15/16situated between the distal-most pair of outlets 1/2 and the interiorpair of outlets 17/18 on the left side of the spreader 100 and outletpairs 22/23, 24/25, 26/27, 28/29, 30/31, 32/33, 34/35 situated betweenthe other distal-most pair of outlets 36/37 and the other interior pairof outlets 20/21 on the right side of the spreader 100.

The 16 outlet pairs 1/2, 3/4, 5/6, 7/8, 9/10, 11/12, 13/14, 15/16,22/23, 24/25, 26/27, 28/29, 30/31, 32/33, 34/35 and 36/37 are providedwith particulate material through the air lines 82 a, 82 b, 82 c, 82 d,82 e, 82 f, 82 g, 82 h, 82 k, 82 l, 82 m, 82 n, 82 o, 82 p, 82 q and 82r, respectively. The interior pair of outlets 17/18 and the centeroutlet 19 are provided with particulate material through the air line 82i, while the other interior pair of outlets 20/21 and the center outlet19 are provided with particulate material through the air line 82 j.

To ensure that the desired amount of particulate material is dispensedthrough each of the outlets 1-37, a plurality of flow dividers 87 areused. Additionally, to ensure that the center outlet 19 is supplied withparticulate material from both the air line 82 i and the air line 82 j,the particulate material is diverted from the air lines 82 i and 82 jthrough branch air lines 88 a and 88 b, respectively.

As best seen in FIG. 12, FIG. 13 and FIG. 14, flow divider 87 a in theform of an adjustable deflector located at a junction between the airline 82 i and the branch air line 88 a ensures that one-fifth of the 2.5units of particulate material delivered from the sluice 55 i to the airline 82 i is diverted into the branch air line 88 a while four-fifths ofthe 2.5 units continues through the air line 82 i. Flow divider 87 b inthe form of an adjustable deflector located at a junction between theair line 82 j and the branch air line 88 b ensures that one-fifth of the2.5 units of particulate material delivered from the sluice 55 j to theair line 82 j is diverted into the branch air line 88 b whilefour-fifths of the 2.5 units continues through the air line 82 j. Thebranch air lines 88 a and 88 b join at a Y-junction to form a joinedbranch air line 88 c, which conveys the particulate material to thecenter outlet 19. Joining the branch air lines 88 a and 88 b combinesthe respective 0.5 unit of particulate material into 1 unit so that 1unit of the particulate material is dispensed by the center outlet 19.The booster hose 84 joins to the joined branch air line 88 c at thecrook of the ‘Y’ to provide extra air flow from behind the particulatematerial flowing from the branch air lines 88 a and 88 b into the joinedbranch air line 88 c. The 2 units of particulate material flowingthrough the air line 82 i downstream of the flow divider 87 a is furtherdivided into two 1 unit portions with the aid of flow divider 87 c inthe form of an adjustable deflector located at a 90-degree bend in theair line 82 i and flow divider 87 d in the form of an adjustabledeflector located at the outlet 18. In this manner, each of the outlets17, 18 of the pair of interior outlets 17/18 dispense 1 unit of theparticulate material. Likewise, the 2 units of particulate materialflowing through the air line 82 j downstream of the flow divider 87 b isfurther divided into two 1 unit portions with the aid of flow divider 87e in the form of an adjustable deflector located at a 90-degree bend inthe air line 82 j and flow divider 87 f in the form of an adjustabledeflector located at the outlet 20. In this manner, each of the outlets20, 21 of the pair of interior outlets 20/21 dispense 1 unit of theparticulate material.

Each of the 16 air lines 82 a, 82 b, 82 c, 82 d, 82 e, 82 f, 82 g, 82 h,82 k, 82 l, 82 m, 82 n, 82 o, 82 p, 82 q and 82 r are equipped with oneflow divider 87 each in the form of an adjustable deflector located atthe respective outlets 2, 4, 6, 8, 10, 12, 14, 16, 22, 24, 26, 28, 30,32, 34 and 36. The 2 units of particulate material supplied to each of82 b, 82 c, 82 d, 82 e, 82 f, 82 g, 82 h, 82 k, 82 l, 82 m, 82 n, 82 o,82 p and 82 q are divided equally into two 1 unit portions so that eachof the two outlets on a given air line dispense 1 unit of theparticulate material. In outermost-extending air lines 82 a and 82 r,the flow divider 87 (labeled as 87 a in FIG. 17 for theoutermost-extending air line 82 a) is adjusted to divide the supplied1.5 units into one 0.5 unit portion and one 1 unit portion so that thepenultimate outlets 2 and 36 of the distal-most pairs of outlets 1/2 and36/37, respectively, dispense 1 unit of the particulate material whileoutermost outlets 1 and 37 of the distal-most pairs of outlets 1/2 and36/37, respectively, dispense 0.5 unit of the particulate material. Whentramlining through the field, the spreader 100 will dispense 1 unit ofthe particulate material to all mid-rows because the outermost outlets 1and 37 will each dispense 0.5 units of the particulate material to thesame outermost mid-row but on immediately subsequent passes. One or moreof the flow dividers 87 may be adjustable to aid in obtaining properdistribution of the particulate material. Adjustable deflectors may beadjustable by any suitable method, for example by mechanical bending(e.g. as at 87 f), by pivoting and clamping in place (e.g. as at 87 b)or by sliding and clamping in place (as at 87 e).

The arrangement of air lines 82 a-82 r in the central airbox 81 offers asignificant advantage with respect to air flow through to the outermostoutlets 1, 37 and to the central outlet 19. Air from the central airbox81 to the center outlet 19 is not required to go through a 180° degreeturn and then a 90° turn before reaching the outlet 19. Therefore, lessenergy is dissipated and less air is required to properly distribute theparticulate material to the center outlet 19. This leaves more air todistribute the particulate material to the interior pairs of outlets17/18 and 20/21. Plugging is avoided or reduced sufficiently and properparticulate material distribution rate is maintained at the centeroutlet 19 and the interior pairs of outlets 17/18 and 20/21. Further,the longest airlines, 82 a and 82 r, are straight having no bends todissipate energy from the air stream, thereby providing sufficient airflow to convey the particulate material the required longer distance atthe proper distribution rate.

Furthermore, use of steel tube for the airlines 82 a-82 r, especiallythe longest airlines, 82 a and 82 r, is more efficient. As the totalboom span of the spreader increases beyond 60 feet, it becomes moreundesirable to use a single steel tube to convey the particulatematerial to a single outlet. The extra weight of one tube per line wouldbe difficult to manage in wider boom weldments. Supporting this extraweight would create a very heavy structure that may be either too heavythereby reducing carrying capacity, or the boom itself may self-destructhaving too much weight out too far from the hopper. By having eachairline convey particulate material to two or more outlets, the amountof steel tube required is lessened, thereby reducing weight and cost ofthe spreader. Furthermore, having each airline convey particulatematerial to two or more outlets, it becomes more feasible to increasethe diameter of the venturis and the airlines in the air manifold, whichpermits increasing flow rate of the particulate material in eachairline, for example to about 120 lb/min/line, thereby successfullydistributing the particulate material at a higher rate at the same orlower vehicle speed, e.g.1200 lb/acre at 10 mph, further out from thevehicle.

As seen in FIG. 18 and FIG. 19, in an alternate embodiment, an air-boom90 of a spreader of the present invention comprises structures similarto the air-boom 80 described above including an alternate embodiment ofan air manifold comprising a central airbox 91, for supporting variouscomponents of the air manifold and for providing air to other parts ofthe air manifold. The air manifold comprises 20 air lines 92 a, 92 b, 92c, 92 d, 92 e, 92 f, 92 g, 92 h, 92 ii, 92 iii, 92 jj, 92 jjj, 92 k, 92l, 92 m, 92 n, 92 o, 92 p, 92 q, 92 r supported on and in fluidcommunication with the airbox 91. The air lines 92 ii and 92 iii aresituated underneath the air lines 92 h and 92 g, respectively, whilelikewise the air lines 92 jj and 92 jjj are situated underneath the airlines 92 k and 92 , respectively, during operation of the air-boom 90.Thus, most of the air lines are situated and extend transversely in thesame horizontal plane, while the air lines 92 ii, 92 iii, 92 jj and 92jjj are situated and extend transversely in a horizontal planeunderneath the other air lines during operation of the air-boom 90.

All twenty of the air lines 92 a-92 r are supplied with particulatematerial from 18 sluices. To this end, the air lines 92 ii and 92 iiiare split from a single feed air line 92 i, the feed air line 92 ireceiving particulate material from one of the sluices. Likewise, theair lines 92 jj and 92 jjj are split from a single feed air line 92 j,the feed air line 92 j receiving particulate material from one of thesluices. As described above, the air lines 92 a and 92 r each receive1.5 units of particulate material, the air lines 92 b, 92 c, 92 d, 92 e,92 f, 92 g, 92 h, 92 k, 92 l, 92 m, 92 n, 92 o, 92 p, 92 q each receive2 units of the particulate material, and the air lines 92 i and 92 jeach receive 2.5 units of the particulate material. Operation of theair-boom 90 is the same as air-boom 80 except for the following.

Outlets 117 and 118 are a pair of interior outlets on the left side, butinstead of being on the same transversely extending interior air line,the outlets 117 and 118 are on different interior air lines 92 iii and92 ii, respectively. Likewise, outlets 120 and 121 are a pair ofinterior outlets on the right side, but instead of being on the sametransversely extending interior air line, the outlets 120 and 121 are ondifferent interior air lines 92 jj and 92 jjj, respectively.

Further, in order for the interior outlets 117, 118, 120 and 121 as wellas a central outlet 119 to each receive 1 unit of the particulatematerial, a somewhat different flow dividing arrangement is utilized.With particular reference to FIG. 19, the single feed air line 92 ireceives 2.5 units of the particulate material. The single feed air line92 i splits into the air lines 92 ii and 92 iii before the air lines 92ii and 92 iii bend to extend transversely. The splitting of the singlefeed air line 92 i into the air lines 92 ii and 92 iii is proximate orat the same location in the single feed air line 92 i as a junction witha branch air line 98 a that carries the particulate material to thecentral outlet 119. The single feed air line 92 i is equipped with twoflow dividers 97 a and 97 c in the form of adjustable deflectors. Theflow divider 97 a is located at the junction between the single feed airline 92 i and the branch air line 98 a to ensure that one-fifth of the2.5 units of particulate material is diverted into the branch air line98 a. The flow divider 97 c is located at the junction between thesingle feed air line 92 i and the air lines 92 ii and 92 iii to ensurethat two-fifths of the 2.5 units of particulate material is divertedinto the air line 92 ii and that two-fifths of the 2.5 units ofparticulate material is diverted into the air line 92 iii. Thus, theflow divider 97 c is located before the bends in the air lines 92 ii and92 iii. Essentially the same arrangement is provided on the right sideof the air-boom 90, utilizing flow divider 97 b to divert one-fifth ofthe 2.5 units of the particulate material from the single feed air line92 j into a branch air line 98 b, and to divert two-fifths of theparticulate material from the single feed air line 92 j into each of theair lines 92 jj and 92 jjj. The two branch air lines 98 a and 98 b joinat a Y-junction to form a joined branch air line 98 c, which conveys theparticulate material to the center outlet 119. In this manner, each ofthe outlets 117, 118, 119, 120 and 121 receives 1 unit of theparticulate material.

Like in the air-boom 80 described above, the air manifold of theair-boom 90 further comprises a booster hose 94 a in fluid communicationwith airbox 91 and the center outlet 119 through the joined branch airline 98 c to provide extra air flow through the center outlet 119 tohelp prevent plugging of the center outlet 119 during operation. In theair-boom 90, four additional booster hoses 94 b, 94 c, 94 d and 94 e influid communication with airbox 91 and the interior outlets 117, 118,120 and 121, respectively, through the air lines 92 iii, 92 ii, 92 jjand 92 jjj, respectively, are provided to provide extra air flow throughthe outlets 117, 118, 120 and 121. FIG. 19 illustrates ports 104 a, 104b, 104 c, 104 d and 104 e in the airbox 91 to which the booster hoses 94a, 94 b, 94 c, 94 d and 94 e, respectively, are connected.

The arrangement illustrated in FIG. 18 and FIG. 19 provides for evenbetter control over the uniformity of distribution of the particulatematerial at the outlets, and provides better uniformity of distributionfor a larger variety of particle types (e.g. particle density) and airflow rates.

The novel features will become apparent to those of skill in the artupon examination of the description. It should be understood, however,that the scope of the claims should not be limited by the embodiments,but should be given the broadest interpretation consistent with thewording of the claims and the specification as a whole.

1. An air-boom spreader for spreading particulate material on a field,the spreader comprising: a hopper for containing the particulatematerial; a metering device for partitioning the particulate material,the metering device comprising first and second metering elements, eachmetering element receiving the particulate material from the hopper, andfirst and second sluice boxes, the first sluice box having a firstplurality of sluices therein that receive the particulate material fromthe first metering element, the second sluice box having a secondplurality of sluices therein that receive the particulate material fromthe second metering element; and, a boom transversely extendible inopposite transverse directions distally from the metering devicesubstantially non-parallel to a direction of travel of the spreader andsubstantially non-perpendicular to the field, the boom comprising aplurality of outlets transversely spaced-apart in a directionperpendicular to the direction of travel of the spreader, the pluralityof outlets comprising a first pair of distal-most outlets situated on afirst side of the spreader, the first pair of distal-most outletscomprising a first outermost outlet and a first penultimate outlet, asecond pair of distal-most outlets situated on a second side of thespreader, the second pair of distal-most outlets comprising a secondoutermost outlet and a second penultimate outlet, a center outletsituated over a central travel line of the spreader, a first pair ofinterior outlets situated between the first pair of distal-most outletsand the center outlet, a second pair of interior outlets situatedbetween the second pair of outermost outlets and the center outlet, anda plurality of air lines connecting the first and second plurality ofsluices to the plurality of outlets for conveying the particulatematerial in an air stream to the plurality of outlets, the plurality ofair lines comprising a first outermost-extending air line connecting afirst outermost-supplying sluice situated among the first plurality ofsluices to the first pair of distal-most outlets, the firstoutermost-supplying sluice supplying a first 1.5 units of theparticulate material to the first outermost-extending air line, thefirst outermost-extending air line configured to convey one-third of thefirst 1.5 units of the particulate material to the first outermostoutlet and two-thirds of the first 1.5 units of the particulate materialto the first penultimate outlet, a second outermost-extending air lineconnecting a second outermost-supplying sluice situated among the secondplurality of sluices to the second pair of distal-most outlets, thesecond outermost-supplying sluice supplying a second 1.5 units of theparticulate material to the second outermost-extending air line, thesecond outermost-extending air line configured to convey one-third ofthe second 1.5 units of the particulate material to the second outermostoutlet and two-thirds of the second 1.5 units of the particulatematerial to the second penultimate outlet, a first centrally-extendingair line connecting a first centrally-supplying sluice situated amongthe first plurality of sluices to the center outlet and the first pairof interior outlets, the first centrally-supplying sluice supplying afirst 2.5 units of the particulate material to the firstcentrally-extending air line, the first centrally-extending air lineconfigured to convey one-fifth of the first 2.5 units of the particulatematerial to the center outlet and two-fifths of the first 2.5 units ofthe particulate material to each outlet of the first pair of interioroutlets, and a second centrally-extending air line connecting a secondcentrally-supplying sluice situated among the second plurality ofsluices to the center outlet and the second pair of interior outlets,the second centrally-supplying sluice supplying a second 2.5 units ofthe particulate material to the second centrally-extending air line, thesecond centrally-extending air line configured to convey one-fifth ofthe second 2.5 units of the particulate material to the center outletand two-fifths of the second 2.5 units of the particulate material toeach outlet of the second pair of interior outlets.
 2. The spreader ofclaim 1, wherein the boom has a span of greater than 60 feet.
 3. Thespreader of claim 1, wherein the boom has a span between 80 feet and 100feet.
 4. The spreader of claim 1, wherein the air-boom further comprisesa blower in fluid communication with the plurality of air lines forproviding the air stream in the plurality of air lines.
 5. The spreaderof claim 1, wherein the plurality of outlets further comprises at leastone first pair of other outlets situated on the first side of thespreader and at least one second pair of other outlets situated on thesecond side of the spreader.
 6. The spreader of claim 5, wherein thefirst pair of interior outlets is situated between the at least onefirst pair of other outlets and the center outlet and the second pair ofinterior outlets is situated between the at least one second pair ofother outlets and the center outlet.
 7. The spreader of claim 1, whereinthe first and second plurality of sluices together comprise a total ofat least 16 sluices and the plurality of outlets comprises a total of atleast 33 outlets.
 8. The spreader of claim 1, wherein the first andsecond plurality of sluices together comprise a total of 18 sluices andthe plurality of outlets comprises a total of 37 outlets.
 9. Thespreader of claim 1, wherein the first and second metering elements areindependently controllable.
 10. The spreader of claim 1, wherein themetering elements comprise endless belts or sets of meter rollers or acombination of at least one endless belt and at least one set of meterrollers.
 11. The spreader of claim 1, wherein each sluice supplies theparticulate material to at least two of the plurality of outlets. 12.The spreader of claim 1, wherein: the first outermost-extending air linecomprises a first flow divider to divide the first 1.5 units of theparticulate material between the first outermost outlet and the firstpenultimate outlet; the second outermost-extending air line comprises asecond flow divider to divide the second 1.5 units of the particulatematerial between the second outermost outlet and the second penultimateoutlet; the first centrally-extending air line comprises a third flowdivider to divide the first 2.5 units of the particulate materialbetween the center outlet and the first pair of interior outlets andcomprises a fourth flow divider to provide each of the outlets of thefirst pair of interior outlets with the respective two-fifths of thefirst 2.5 units, the second centrally-extending air line comprises afifth flow divider to divide the second 2.5 units of the particulatematerial between the center outlet and the second pair of interioroutlets and comprises a sixth flow divider to provide each of theoutlets of the second pair of interior outlets with the respectivetwo-fifths of the second 2.5 units.
 13. The spreader of claim 12,wherein: the first centrally-extending air line splits into: a firstbranch air line in fluid communication with the center outlet; a firstinterior air line in fluid communication with one of the outlets of thefirst pair of interior outlets; and, a second interior air line in fluidcommunication with the other of the outlets of the first pair ofinterior outlets, wherein: the third flow divider diverts one-fifth ofthe particulate material from the first centrally-extending air lineinto the first branch air line; and, the fourth flow divider divertstwo-fifths of the particulate material from the firstcentrally-extending air line into each of the first and second interiorair lines, whereby the first interior air line and the second interiorair line both have bends so that the first and second interior air linesextend transversely, and the fourth flow divider is situated before thebends in the first and second interior air lines; and, the secondcentrally-extending air line splits into: a second branch air line influid communication with the center outlet; a third interior air line influid communication with one of the outlets of the second pair ofinterior outlets; and, a fourth interior air line in fluid communicationwith the other of the outlets of the second pair of interior outlets,wherein: the fifth flow divider diverts one-fifth of the particulatematerial from the second centrally-extending air line into the secondbranch air line; and, the sixth flow divider diverts two-fifths of theparticulate material from the second centrally-extending air line intoeach of the third and fourth interior air lines, whereby the thirdinterior air line and the fourth interior air line both have bends sothat the third and fourth interior air lines extend transversely, andthe sixth flow divider is situated before the bends in the third andfourth interior air lines.
 14. An air-boom spreader for spreadingparticulate material to mid-rows between crop rows on a field, thespreader comprising: a hopper for containing the particulate material; ametering device configured to receive the particulate material from thehopper; a plurality of outlets transversely spaced-apart on a boom in adirection perpendicular to a direction of travel of the spreader andconfigured to receive the particulate material from the metering deviceand to dispense the particulate material to the mid-rows, the pluralityof outlets comprising a pair of distal-most outlets in relation to themetering device, the pair of distal-most outlets comprising an outermostoutlet and a penultimate outlet, an innermost outlet in relation to themetering device, and a pair of interior outlets situated on the boombetween the pair of distal-most outlets and the innermost outlet; and, aplurality of air lines connecting the metering device to the pluralityof outlets for conveying the particulate material in an air stream tothe plurality of outlets, the plurality of air lines comprising a firstair line connecting the metering device to the pair of distal-mostoutlets, the metering device supplying 1.5 units of the particulatematerial to the first air line, the first air line configured to conveyone-third of the 1.5 units of the particulate material to the outermostoutlet and two-thirds of the 1.5 units of the particulate material tothe penultimate outlet, a second air line connecting the metering deviceto the innermost outlet and the pair of interior outlets, the meteringdevice supplying 2.5 units of the particulate material to the second airline, the second air line configured to convey one-fifth of the 2.5units of the particulate material to the innermost outlet and two-fifthsof the 2.5 units of the particulate material to each outlet of the pairof interior outlets.
 15. The spreader of claim 14, wherein the innermostoutlet is over a central travel line of the spreader.
 16. The spreaderof claim 14, wherein the plurality of outlets further comprises at leastone pair of other outlets situated on the boom between the pair ofdistal-most outlets and the pair of interior outlets, and the at leastone pair of other outlets are supplied with the particulate materialthrough at least one other air line.
 17. The spreader of claim 14,wherein the air-boom further comprises a blower in fluid communicationwith the plurality of air lines for providing the air stream in theplurality of air lines.
 18. The spreader of claim 14, wherein themetering device comprises one or more metering elements, and the one ormore metering elements comprises an endless belt or a set of meterrollers.
 19. The spreader of claim 14, wherein: the first air linecomprises a first flow divider to divide the 1.5 units of theparticulate material between the outermost outlet and the penultimateoutlet; and, the second air line comprises a second flow divider todivide the 2.5 units of the particulate material between the innermostoutlet and the pair of interior outlets and comprises a third flowdivider to provide each of the outlets of the pair of interior outletswith the respective two-fifths of the 2.5 units.
 20. The spreader ofclaim 19, wherein: the pair of interior outlets comprises a firstinterior outlet and a second interior outlet; the first interior outletis situated on a first interior air line, the first interior air linehaving a first bend so that the first interior air line extendstransversely, the first interior outlet situated after the first bend;the second interior outlet is situated on a second interior air lineseparate from the first interior air line, the second interior air linehaving a second bend so that the second interior air line extendstransversely, the second interior outlet situated after the second bend;and, the second flow divider divides the particulate material betweenthe first and second interior air lines, the second flow dividersituated before the first and second bends.
 21. An air-boom spreader forspreading particulate material on a field, the spreader comprising: ahopper for containing the particulate material; a metering devicecomprising a plurality of sluices, the metering device receiving theparticulate material from the hopper and partitioning the particulatematerial into the plurality of sluices; a plurality of outletstransversely spaced-apart on a boom in a direction perpendicular to adirection of travel of the spreader; and, a plurality of air linesconnecting the plurality of sluices to the plurality of outlets forconveying the particulate material in an air stream from the pluralityof sluices to the plurality of outlets, wherein there are more thantwice as many outlets as there are sluices, and wherein the plurality ofoutlets comprises an innermost outlet, an outermost outlet and at leastthree other outlets between the innermost outlet and the outermostoutlet whereby the innermost outlet and the outermost outlet are eachsupplied with half as much of the particulate material as each of the atleast three other outlets.
 22. The spreader of claim 21, wherein themetering device comprises one or more metering elements for receivingthe particulate material from the hopper.
 23. The spreader of claim 21,wherein the metering device comprises two or more metering elements forreceiving the particulate material from the hopper.